There are a lot of differences Omer, its a whole new car and looks a lot different, have a look at the shot on autosport, and Williams have done a good job with this "spying video" lol.
Yep nice PR video from Williams (nice way to launch the new car). If anyone has doubts it is PR... Ask yourself why the 'spy' is standing less than 20ft from the car and can clearly be seen in the reflection of the passenger window of the car he is standing behind (the car that is about 15ft from the truck ).
If it was this easy to spy on Williams, all the other teams would be there as well .